As supply and use of portable terminals are increasing, a high speed process is required in data treatment of portable terminals and low power consumption is regarded as important in connection with a battery life of the portable terminals. A current memory circuit using a SI (Switched-Current) circuit is attracting attention because the SI is capable of implementing high speed data treatment with low power consumption.
FIG. 1 is a drawing illustrating a conventional current memory circuit.
As illustrated in FIG. 1, the conventional current memory circuit uses a bias current on the basis of a current mirror. A drain current may be expressed as the sum of a bias current J and an incoming current I-in in the current mirror implemented by an N-type MOS (MOSFET) having a common gate. Therefore, the sum of the bias current J and the incoming current I-in is stored between a gate and a source of the current mirror, i.e., a memory capacitor. Accordingly, the conventional current memory circuit has a problem of high power consumption arising from a use of the bias current.
In addition, clock feedthrough occurs in the current memory circuit, wherein the clock feedthrough is a leaking of stored energy toward the direction of the switch supplying the incoming current due to nonlinear operation of a transistor and non-conformity of a process. Furthermore, in the case an error occurring due to the clock feedthrough is greater than the incoming current I-in, a problem may occur that the incoming current is entirely dissipated. That is, since the clock feedthrough decreases a voltage stored in the memory capacitor of the current memory circuit, there is a problem in the data treatment in that an error is induced in the accuracy of the stored memory and in the sustainment time of the stored memory.